A trailer released for the forthcoming documentary by director/writer Dana Nachman spotlights the day San Francisco turned into Gotham City for five-year-old Miles Scott, and the thousands of people who showed up to watch this “Batkid” save the city.

“One of his doctors told us that with this disease they just become like a fighter, you know? They have to be,” Miles’ father Nick said of his son’s leukemia diagnosis. “They fight for life, and so I think he sees the good versus evil battle in superheroes and just relates to it.”

Miles was obsessed with all things superhero, according to his parents, but it always came back to Batman. His wish to the Make-a-Wish foundation was, “I wish to be a real Batman.”

The documentary will follow how that simple wish touched the hearts of so many Americans on November 15, 2013, turning a special day for one boy into a day that the whole country will remember. The city of San Francisco orchestrated several elaborate stunts and “rescues” for Batkid, while 25,000 spectators watched in person and countless more followed his every move via social media

Moving Train Inc., a non-profit that funds documentary films, is partnering on the project. Producers have teamed with big-name industry professionals, like composer Hans Zimmer, who have agreed to work at reduced rates to bring the post-production price tag to $100,000.